Question
I'm thinking of starting a blog/magazine around a topic but I don't see many competitors which concerns me.
I want to start an online magazine reviewing products in a niche. When I go on to Google Keyword Planner I see there are 10k-100k searches a month in the area, and opportunities to branch out in similar areas, but I don't see a ton of competitors.
This concerns me that the topic isn't profitable.
How can I know if the topic would be a profitable one?
I don't want to waste years building something only to find that the niche isn't a good one to be in and I should have picked something else.
Answer
Pamela is right. Any topic will work. The key is that you have to immerse yourself in that industry, so you should be passionate about it. You can't just depend on passively posting on the blog—the blog is just your entry point.
You will need to build relationships (online and offline) with others in your topic and eco-system. You have to become known in your industry. Then people will follow your blog, you can speak, etc.
Once you become involved in the industry, you will have opportunities to make money.
But, if you want to do it right, and go big, ignore making penny ante money through google (or anyone's ads) or sponsored posts. Focus on building credibility and making real links with people in your industry.
